TABLE I.
Main characteristics of the four devices compared in this study. SPL represents the sound pressure level, f0 represents the fundamental frequency, and Dt represents the phonation time percentage.
| Device | Type of transducer | Frame length | Calibration procedure for SPL | Estimated parameters | Algorithm for f0 evaluation | Uncertainty reported in literature |
|---|---|---|---|---|---|---|
| VocaLog2 | Contact microphone | 1 s | Yes | SPL | NA | SPL mean error of 1.3–1.9 dB in a vowel task and of 1.5–2.4 dB in a reading task |
| VoxLog | Accelerometer and calibrated air microphone | 0.1 s, 1 s, 5 s, 30 s, 60 s, 180 s and 300 s | No | A-weighted SPL for voice and noise, f0, Dt | Fast Fourier Transform- based | SPL mean error 4.3 dB, f0 mean error of −0.56 Hz |
| Voice Care | Contact microphone | 0.03 s | Yes | SPL, f0, Dt | Autocorrelation-based | SPL mean error −1.6 dB and standard deviation 2.5 dB, f0 absolute error ≤ 3 Hz |
| APM3200 | Accelerometer | 0.05 s | Yes | SPL, f0, Dt and other parameters derived from the previous ones | Autocorrelation-based | SPL mean error 3.2 dB with a standard deviation of 6 dB, f0 error 1 Hz |